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iov_iter/hardening: move object size checks to inlined part
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There we actually have useful information about object sizes.
Note: this patch has them done for all iov_iter flavours.
Right now we do them twice in iovec case, but that'll change
very shortly.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed Jun 30, 2017
1 parent b0377fe commit aa28de2
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Showing 2 changed files with 64 additions and 16 deletions.
58 changes: 53 additions & 5 deletions include/linux/uio.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
#define __LINUX_UIO_H

#include <linux/kernel.h>
#include <linux/thread_info.h>
#include <uapi/linux/uio.h>

struct page;
Expand Down Expand Up @@ -91,11 +92,58 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);

size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);

static __always_inline __must_check
size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
if (unlikely(!check_copy_size(addr, bytes, true)))
return bytes;
else
return _copy_to_iter(addr, bytes, i);
}

static __always_inline __must_check
size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
if (unlikely(!check_copy_size(addr, bytes, false)))
return bytes;
else
return _copy_from_iter(addr, bytes, i);
}

static __always_inline __must_check
bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
{
if (unlikely(!check_copy_size(addr, bytes, false)))
return false;
else
return _copy_from_iter_full(addr, bytes, i);
}

static __always_inline __must_check
size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
if (unlikely(!check_copy_size(addr, bytes, false)))
return bytes;
else
return _copy_from_iter_nocache(addr, bytes, i);
}

static __always_inline __must_check
bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
if (unlikely(!check_copy_size(addr, bytes, false)))
return false;
else
return _copy_from_iter_full_nocache(addr, bytes, i);
}

size_t iov_iter_zero(size_t bytes, struct iov_iter *);
unsigned long iov_iter_alignment(const struct iov_iter *i);
unsigned long iov_iter_gap_alignment(const struct iov_iter *i);
Expand Down
22 changes: 11 additions & 11 deletions lib/iov_iter.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -535,7 +535,7 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
return bytes;
}

size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
const char *from = addr;
if (unlikely(i->type & ITER_PIPE))
Expand All @@ -550,9 +550,9 @@ size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)

return bytes;
}
EXPORT_SYMBOL(copy_to_iter);
EXPORT_SYMBOL(_copy_to_iter);

size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
if (unlikely(i->type & ITER_PIPE)) {
Expand All @@ -569,9 +569,9 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)

return bytes;
}
EXPORT_SYMBOL(copy_from_iter);
EXPORT_SYMBOL(_copy_from_iter);

bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
if (unlikely(i->type & ITER_PIPE)) {
Expand All @@ -594,9 +594,9 @@ bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
iov_iter_advance(i, bytes);
return true;
}
EXPORT_SYMBOL(copy_from_iter_full);
EXPORT_SYMBOL(_copy_from_iter_full);

size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
if (unlikely(i->type & ITER_PIPE)) {
Expand All @@ -613,9 +613,9 @@ size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)

return bytes;
}
EXPORT_SYMBOL(copy_from_iter_nocache);
EXPORT_SYMBOL(_copy_from_iter_nocache);

bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
if (unlikely(i->type & ITER_PIPE)) {
Expand All @@ -637,7 +637,7 @@ bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
iov_iter_advance(i, bytes);
return true;
}
EXPORT_SYMBOL(copy_from_iter_full_nocache);
EXPORT_SYMBOL(_copy_from_iter_full_nocache);

size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
Expand All @@ -663,7 +663,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
}
if (i->type & (ITER_BVEC|ITER_KVEC)) {
void *kaddr = kmap_atomic(page);
size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
size_t wanted = _copy_from_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
return wanted;
} else
Expand Down

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